Conventional wheelchairs have large wheels and caster wheels rotatably mounted on axles and spindles secure to frames. An example of wheelchairs are disclosed by K. S. Rodaway in U.S. Pat. No. 3,857,606 and J. L. Shriver in U.S. Pat. Des. 359,260. The frames of conventional wheelchairs have metal plates and tubular members secured together with welds. The welding of wheelchair frames is labor intensive and an expensive fabrication operation. The components of welded wheelchair frames are not adjustable to allow for different wheelchair sizes and dimensions. Individual wheelchair frames must be welded for different wheelchair designs, sizes, and shapes. Wheelchairs with broken welded frames are not repaired at the user's location. They are shipped to a welding shop or the manufacturer for repairs and part replacements. A replacement wheelchair must be available for the user. Conventional wheelchairs have relatively wide dimensions and external side wheels which restrict movement along narrow doorways and walkways, such as the passenger walkways of commercial aircraft. These wheelchairs are not useable to transport relatively immobile and physically challenged persons to and from seats on a commercial aircraft.